Saturday, May 16, 2015

ALD protected Lithium Metal Anodes with improved capacity retention

University of Maryland demonstrate atomic layer deposition (ALD) of protection layers directly on Li metal with exquisite thickness control. They show that 14 nm thick, ALD Al2O3 layer can protect the Li surface from corrosion due to atmosphere, sulfur, and electrolyte exposure. Using Li-S battery cells as a test system, an improved capacity retention using ALD protected anodes over cells assembled with bare Li metal anodes for up to 100 cycles was shown.

Lithium metal is considered the most promising anode for next-generation batteries due to its high energy density of 3840 mAhg-1. However, the extreme reactivity of the Li surface can induce parasitic reactions with solvents, contamination, and shuttled active species in the electrolyte, reducing performance of batteries employing Li metal anodes. One promising solution to this issue is application of thin chemical protection layers to the Li metal surface. Using a custom made ultrahigh vacuum (UHV) integrated deposition and characterization system, we demonstrate atomic layer deposition (ALD) of protection layers directly on Li metal with exquisite thickness control. We demonstrate as a proof of concept that a 14 nm thick, ALD Al2O3 layer can protect the Li surface from corrosion due to atmosphere, sulfur, and electrolyte exposure. Using Li-S battery cells as a test system, we demonstrate an improved capacity retention using ALD protected anodes over cells assembled with bare Li metal anodes for up to 100 cycles.